Crosslinkable polycyclic polycarbonate oligomers and method for their preparation

ABSTRACT

Polycyclic polycarbonate (or thiol analog) oligomers are prepared from a mixture of at least one bishaloformate with at least one tetraphenol, or thio analogs thereof. Such mixture may also contain at least one dihydroxy or dimercapto compound. The oligomers are formed by the reaction of such mixtures with alkali metal hydroxides and various amines. The polycyclic oligomer mixtures may be converted to crosslinked polycarbonates or their thiol analogs.

This is a division of application Ser. No. 801,437, filed Nov. 25, 1985,now abandoned.

This invention relates to new polycyclic oligomeric compositions,methods for their preparation and uses thereof. In particular, itrelates to crosslinkable cyclic polycarbonate oligomers.

Polycarbonates are well known polymers which have good propertyprofiles, particularly with respect to impact resistance, electricalproperties, optical clarity, dimensional rigidity and the like. Thesepolymers are generally linear, but can be made with branched sites toenhance their properties in specific ways. Low levels of branching aregenerally incorporated into the resin by copolymerizing into the polymerbackbone a polyfunctional reagent to yield a thermoplastic polycarbonateresin with enhanced rheological properties and melt strength which makeit particularly suitable for such types of polymer processing proceduresas the blow molding of large, hollow containers and the extrusion ofcomplex profile forms. Special manufacturing runs must be set aside toprepare these branched polycarbonate resins.

Sufficiently higher levels of branching sites in the resin will causeresin chains actually to join to each other to form partially or fullycrosslinked resin networks which will no longer be thermoplastic innature and which are expected to exhibit enhancements over correspondinglinear resins in physical properties and/or in their resistance toabusive conditions, such as exposure to organic solvents. A wide varietyof means have been employed to produce crosslinking in polycarbonateresins. They generally involve the incorporation of a suitably reactivechemical group into the resin chain at its time of manufacture, as anadditive to the resin after manufacture, or both. These reactive groupsand the reactions they undergo are generally different from thosecharacteristic of polycarbonate resins themselves and therefore tend tohave detrimental side effects on the physical and/or chemical propertiesof the polymer. The conventional test used to judge the success of thesemeans for crosslinking is to observe the formation of gels due to thecrosslinked material when a resin sample is mixed with a solvent, suchas methylene chloride, in which normal linear polycarbonate resin ishighly soluble.

A principal object of the present invention, therefore, is to provideuseful new compositions of matter, and methods for their preparation anduse.

A further object is to provide compositions which form crosslinkedpolycarbonates, and precursors therefor.

A still further object is to provide new polycarbonate compositions withadvantageous properties.

Other objects will in part be obvious and will in part appearhereinafter.

In on of its aspects, the present invention includes compositionscomprising polycyclic oligomers having structural units of both of theformulas PG,4 ##STR1## wherein: each R¹ is independently a divalentaliphatic, alicyclic or aromatic radical;

each of A¹ and A² is a trivalent aromatic radical;

each Y¹ is independently oxygen or sulfur; and

Y² is a bridging radical in which one or two atoms separate A¹ from A².

Before proceeding with a detailed discussion of the invention, it may beuseful to explain some terms used herein. The term "thiol analog", whenused with reference to dihydroxy compounds, oligomers andpolycarbonates, includes monothio and dithio compounds in which thecarbon-sulfur bonds are single bonds only. The terms "resin" and"resinous composition" include polycarbonates and polymers containingthiol analogs of the carbonates.

As will be apparent from the above, the polycyclic oligomers of thisinvention may contain organic carbonate, thiolcarbonate and/ordithiolcarbonate units. The various R¹ values in formula I may bedifferent but are usually the same, and may be aliphatic, alicyclic,aromatic or mixed; those which are aliphatic or alicyclic generallycontain up to about 8 carbon atoms. Suitable R¹ values include ethylene,propylene, trimethylene, tetramethylene, hexamethylene, dodecamethylene,1,4-(2-butenylene), 1,10-(2-ethyldecylene), 1,3-cyclopentylene,1,3-cyclohexylene, 1,4-cyclohexylene, m-phenylene, p-phenylene,4,4'-biphenylene, 2,2-bis(4-phenylene)propane, benzene-1,4-dimethylene(which is a vinylog of the ethylene radical and has similar properties)and similar radicals such as those which correspond to the dihydroxycompounds disclosed by name or formula (generic or specific) in U.S.Pat. No. 4,217,438, the disclosure of which is incorporated by referenceherein. Also included are radicals containing non-hydrocarbon moieties.These may be substituents such as chloro, nitro, alkoxy and the like,and also linking radicals such as thio, sulfoxy, sulfone, ester, amide,ether and carbonyl. Most often, however, all R¹ radicals are hydrocarbonradicals.

Preferably at least about 60% and more preferably at least about 80% ofthe total number of R¹ values in the polycyclic oligomers, and mostdesirably all of said R¹ values, are aromatic. The aromatic R¹ radicalspreferably have the formula

    --A.sup.3 --Y.sup.3 --A.sup.4 --                           (III)

wherein each of A³ and A⁴ is a single-ring divalent aromatic radical andY³ is a bridging radical in which one or two atoms separate A³ from A⁴.The free valence bonds in formula III are usually in the meta or parapositions of A³ and A⁴ in relation to Y³ Such R¹ values may beconsidered as being derived from bisphenols of the formula HO--A³ --Y³--A⁴ --OH. Frequent reference to bisphenol will be made hereinafter, butit should be understood that R¹ values derived from suitable compoundsother than bisphenols may be employed as appropriate.

In formula III, the A³ and A⁴ values may be unsubstituted phenylene orsubstituted derivatives thereof, illustrative substituents (one or more)being alkyl, alkenyl (e.g., crosslinkable-graftable moieties such asvinyl and allyl), halo (especially chloro and/or bromo), nitro, alkoxyand the like. Unsubstituted phenylene radicals are preferred. Both A³and A⁴ are preferably p-phenylene, although both may be o- orm-phenylene or one o- or m-phenylene and the other p-phenylene.

The bridging radical, Y³, is one in which one or two atoms, preferablyone, separate A³ from A⁴. It is most often a hydrocarbon radical andparticularly a saturated radical such as methylene, cyclohexylmethylene,neopentylidene, 2-[2.2.1]bicycloheptylmethylene, ethylene, ethylidene,isopropylidene, cyclohexylidene, cyclopentadecylidene, cyclododecylideneor adamantylidene, especially an alkylidene radical. Also included,however, are unsaturated radicals and radicals which are entirely orpartially composed of atoms other than carbon and hydrogen. Examples ofsuch radicals are 2,2-dichloroethylidene, carbonyl, thio and sulfone.oor reasons of availability and particular suitability for the purposesof this invention, the preferred radical of formula III is the2,2-bis(4-phenylene)propane radical, which is derived from bisphenol Aand in which Y³ is isopropylidene and A³ and A⁴ are each p-phenylene.

As noted, each Y¹ value is independently oxygen or sulfur. Most often,all Y¹ values are oxygen and the corresponding compositions are cyclicpolycarbonate oligomer mixtures.

An essential feature of the compositions of this invention is thepresence therein of structural units having formula II, which lead to anoverall polycyclic structure. The number of rings in any individualmolecule of said compositions will depend on the proportions ofreactants and the reaction conditions. The following molecularstructures are illustrative. ##STR2## wherein m and n are integers,typically from 1 to about 11.

In formula II, each Y¹ value may be oxygen or sulfur and all Y¹ valuesare usually oxygen. The Y² values are bridging radicals similar to thosedefined hereinabove for Y³, and are usually methylene, carbonyl, thiol,sulfoxy or sulfone. The A¹ and A² values are usually trivalentsingle-ring aromatic radicals; they are preferably unsubstituted but maycontain substituents such as those previously identified with respect toA³ and A⁴.

The structural units of formula II may be considered as being derivedfrom the corresponding tetraphenols and their thiol analogs.Illustrative tetraphenols are bis(2,4-dihydroxy-3-methylphenyl)methane,2,2',4,4'-tetrahydroxybiphenyl, 2,2',4,4'-tetrahydroxybenzophenone,bis(2,4-dihydroxyphenyl) sulfide, bis(2,4-dihydroxyphenyl) sulfoxide andbis(2,5-dihydroxyphenyl) sulfone.

Certain of these tetraphenols, particularly thebis(2,4-dihydroxy-3-alkylphenyl)methanes, are novel compounds.Therefore, another aspect of the invention is tetraphenols having theformula ##STR3## wherein R² is a C₁₋₄ primary or secondary alkyl radicaland especially methyl.

Such tetraphenols may be prepared by reacting a 2-alkylresorcinol withformaldehyde under acidic conditions, typically in aqueous solution andat a temperature in the range of 10°-50° C. Most often, approximatelyequimolar amounts of 2-alkylresorcinol and acid are present and themolar ratio of 2-alkylresorcinol to formaldehyde is about 3-6:1. Thefollowing example is illustrative. All parts are by weight.

EXAMPLE 1

To a solution of 248.14 parts (2 moles) of 2-methylresorcinol in oneliter of 2 N aqueous hydrochloric acid was added 32.6 parts of 38%aqueous formaldehyde solution (0.4 mole of formaldehyde). The mixturewas stirred for two hours at about 20° C., whereupon a white solidprecipitated. It was removed by filtration, washed several times withwater and dried. The product was shown by infrared and nuclear magneticresonance spectroscopy to be the desiredbis(2,4-dihydroxy-3-methylphenyl)methane. The yield was 49.2 parts, or50% of theoretical.

The polycyclic oligomers of this invention include dimers, trimers andtetramers similar to those disclosed in the following U.S. Pat. Nos.:

    ______________________________________                                               3,155,683                                                                            3,386,954                                                              3,274,214                                                                             3,422,119.                                                     ______________________________________                                    

They also include polycyclic oligomer mixtures similar to the mixturesdisclosed in copending, commonly owned application Ser. No. 704,122,filed Feb. 22 1985, the disclosure of which is incorporated by referenceherein.

The polycyclic oligomer mixtures consist essentially of oligomers havingdegrees of polymerization from 2 to about 30 and preferably to about 20,with a major proportion being up to about 12 and a still largerproportion up to about 15. Since they are mixtures, these compositionshave relatively low melting points as compared to single compounds. Thepolycyclic oligomer mixtures are generally liquid at temperatures above300° C. and most often at temperatures above 225° C.

The mixtures of this invention contain very low proportions of acyclicoligomers, generally undetectable amounts and very seldom more thanabout 5% by weight. They also contain low percentages, frequently lessthan 30%, of polymers (linear or cyclic) having a degree ofpolymerization greater than about 30. Such polymers are frequentlyidentified hereinafter as "high polymer". These properties, coupled withthe relatively low melting points and viscosities of the polycyclicoligomer mixtures, contribute to their utility in the invention.

The polycyclic oligomers of this invention may be prepared by acondensation reaction involving at least one compound selected from thegroup consisting of bishaloformates and thio analogs thereof, saidcompounds having the formula

    R.sup.1 (Y.sup.1 COX.sup.1).sub.2                          (VII)

and at least one compound selected from the group consisting oftetraphenols and thiol analogs thereof, said compounds having theformula

    (HY.sup.1).sub.2 A.sup.1 --Y.sup.2 --A.sup.2 (Y.sup.1 H).sub.2 (VIII)

wherein R¹, A¹, A², Y¹ and Y² are as defined hereinabove and X¹ ischlorine or bromine. The condensation reaction typically takes placeinterfacially when a solution of said compounds in a substantiallynon-polar organic liquid is contacted with a tertiary amine from aspecific class and an aqueous alkali metal hydroxide solution.

Accordingly, another embodiment of the present invention is a method forpreparing a composition comprising polycyclic polycarbonate or thiolanalog oligomers which comprises contacting (A) a composition comprisinga mixture of (1) at least one compound having formula VII and (2) atleast one compound of formula VIII, said mixture optionally alsocontaining (3) at least one bis(active hydrogen) compound having theformula

    R.sup.3 (Y.sup.3 H).sub.2,                                 (IX)

wherein each Y³ is independently sulfur when the corresponding R³ isaliphatic or alicyclic and oxygen or sulfur when the the correspondingR³ is aromatic, with

(B) at least one oleophilic aliphatic or heterocyclic tertiary amine and

(C) an aqueous alkali metal hydroxide solution having a concentration ofabout 0.1-10 M;

said contact being effected under conditions resulting in high dilutionof reagent A,. or the equivalent thereof, in a substantially non-polarorganic liquid which forms a two-phase system with water, for a periodof time sufficient to form said polycyclic oligomers; and recoveringsaid oligomers.

Reagent A, as indicated, is a composition comprising a mixture ofcompounds of formulas V and VI (reagents A-1 and A-2, respectively) and,optionally, compounds of formula VI (reagent A-3). It may also containother compounds, including oligomers of the formula ##STR4## wherein R¹,Y¹ and X¹ are as previously defined and n is a small number, typicallyabout 1-4.

While the X¹ values in formulas VII and X may be chlorine or bromine,the bischloroformates, in which X¹ is chlorine, are most readilyavailable and their use is therefore preferred. The compounds of formulaVIII may be tetraphenols or mono- or polythiol analogs thereof, with thetetraphenols being preferred. (Frequent reference to bischloroformaeesand tetraphenols will be made hereinafter, but it should be understoodthat all compounds of formulas VII and VIII, respectively, areincluded.)

Suitable bis(active hydrogen) compounds of formula IX (reagent A-3)include diols and thiol analogs thereof having divalent radicals offormula III which are different from the corresponding divalent radicalsin the compound of foruula VII, as well as other dihydroxyaromaticcompounds and thiol analogs thereof. .Any cyclic oligomers containingdivalent aliphttic radicals (or their vinylogs) flanked by two oxygenatoms are bbtained from a mixture of compounds identifiable as reagentA-1.

The proportion of reagent A-2 in the reaction mixture (and of units offormula II in the oligomer product) depends to some extent on the amountof crosslinking desired in the final linear polycarbqnate. In general,about 0.5-10.0 mole percent (based on monomeric units in total reagentA), and especially about 1-5 mole percent, will produce a crosslinkedproduct having the desired properties.

However, it is within the scope of the invention to prepare a polycyclicoligomer product having a higher proportion of units of formula II andto dilute it with a conventional cyclic oligomer product prior toformation of the crosslinked linear polycarbonate. Therefore, thepresence of about 0.5-12.0 mole percent of component A-2 iscontemplated. Higher proportions than about 12 mole percent may causepremature crosslinking via formation of branched polycarbonates,resulting in gel formation. Reagent A-3, when present, generallycomprises up to about 50% by weight, most often up to about 20% andpreferably up to about 10%, of total reagent A.

The bischloroformate may be employed in substantially pure, isolatedform or as a cuude bischloroformate product. Suitable crude products maybe prepared by any known methods for bischooroformate preparation.Typically, at least one bisphenol is reacted with phosgene in thepresence of a substantially inert organic liquid, as disclosed in thefollowing U.S. Pat.:

    ______________________________________                                               3,255,230                                                                            3,966,785                                                              3,312,661                                                                             3,974,126.                                                     ______________________________________                                    

The disclosures of these patents are incorporated by reference herein.In addition to the bisphenol bischloroformate, such crudebischloroformate products may contain oligomer bischloroformatescontaining up to 4 bisphenol units. They may also contain minor amountsof higher oligomer bischloroformates and of monochloroformatescorresponding to any of the aforementioned bischloroformates. Higherligomer monoand bischloroforaates are preferably present, if at all,only in trace amounts.

More preferably, the preparation of the crude bischloroformate producttakes place in the presence of aqueuus alkali. The pH of the reactionmixture may be up to about 12. It is generally found, however, that theproportion of high polymer in the cyclic oligomer mixture is minimizedby employing a crude bischloroformate product comprising a major amountof bisphenol bischloroformate and only minor amounts of any oligomerbischloroformates. Such products may be obtained by the method disclosedin copending, commonly assigned application Ser. No. 790,909, filed Oct.24, 1985, the disclosure of which is also incorporated by referenceherein. In that method, phosgene is passed into a mixture of asubstantially inert organic liquid and a bisphenol, said mixture beingmaintained at a temperature within the range of about 10°-40° C., thephosgene flow rate being at least 0.15 equivalent per equivalent ofbisphenol per minute when the temperature is above 30° C. An aqueousalkali metal or alkaline earth metal base solution is simultaneouslyintroduced as necessary to maintain the pH of the aqueous phase in therange of 0.5-8. By this method, it is possible to preparebischloroformate in high yield while using a relatively small proportionof phosgene, typically up to about 1.1 equivalent per equivalent ofbisphenol.

When one of these methods is employed, it is obvious that the crudebischloroformate product will ordinarily be obtained as a solution in asubstantially non-polar organic liquid such as those disclosedhereinafter. Depending on the method of preparation, it may be desirableto wash said solution with a dilute aqueous acidic solution to removetraces of base used in preparation.

The tertiary amines useful as reagent B ("tertiary" in this contextdenoting the absence of N--H bonds) generally comprise those which areoleophilic (i.e., which are soluble in and highly active in organicmedia, especially those used in the oligomer preparation method of thisinvention), and more particularly those which are useful for theformation of polycarbonates. Reference is made, for example, to thetertiary amines disclosed in the aforementioned U.S. Pat. Nos. 4,217,438and in 4,368,315, the disclosure of which is also incorporated byreference herein. They include aliphatic amines such as triethylamine,tri-n-propylamine, diethyl-n-propylamine and tri-n-butylamine and highlynucleophilic heterocyclic amines such as 4-dimethylaminopyridine (which,for the purposes of this invention, contains only one active aminegroup). The preferred amines are those which dissolve preferentially inthe organic phase of the reaction system; that is, for which theorganic-aqueous partition coefficient is greater than 1. This is truebecause intimate contact between the amine and reagent A is essentialfor the formation of the cyclic oligomer mixture. For the most part,such amines contain at least about 6 and preferably about 6-14 carbonatoms.

The amines most useful as reagent B are trialkylamines containing nobranching on the carbon atoms in the 1- and 2- positions. Especiallypreferred are tri-n-alkylamines in which the alkyl groups contain up toabout 4 carbon atoms. Triethylamine is most preferred by reason of itsparticular availability, low cost, and effectiveness in the preparationof products containing low percentages of linear oligomers and highpolymers.

Reagent C is an aqueous alkali metal hydroxide solution. It is mostoften lithium, sodium or potassium hydroxide, with sodium hydroxidebeing preferred because of its availability and relatively low cost. Theconcentration of said solution is about 0.2-10 M and preferably nohigher than about 3 M.

The fourth essential component in the cyclic oligomer preparation methodof this invention is a substantially non-polar organic liquid whichforms a two-phase system with water. The identity of the liquid is notcritical, provided it possesses the stated properties. Illustrativeliquids are aromatic hydrocarbons such as toluene and xylene;substituted aromatic hydrocarbons such as chlorobenzene,o-dichlorobenzene and nitrobenzene; chlorinated aliphatic hydrocarbonssuch as chloroform and methylene chloride; and mixtures of the foregoingwith ethers such as tetrahydrofuran.

To prepare the cyclic oligomer mixture according to the above-describedmethod, the reagents and components are maintained in contact underconditions wherein reagent A is present in high dilution, or equivalentconditions. Actual high dilution conditions, requiring a largeproportion of organic liquid, may be employed but are usually notpreferred for cost and convenience reasons. Instead, simulated highdilution conditions known to those skilled in the art may be employed.For example, in one embodiment of the method reagent A (i.e., acombination of all constituents thereof) or reagents A and B are addedgradually to a mixture of the other materials. It is within the scope ofthis embodiment to incorporate reagent B in the mixture to which reagentA is added, or to add it gradually, either in admixture with reagent Aor separately. Continuous or incremental addition of reagent B isfrequently preferred, whereupon the cyclic oligomer mixture is obtainedin relatively pure form and in high yield.

Although addition of reagent A neat (i.e., without solvents) is wtthinthe scope of this embodiment, it is frequently inconvenient because manybischloroformates are solids. Therefore, it is preferably added as asolution in a portion of the organic liquid. The proportion of organicliquid used for this purpose is not critical; about 25-75% by weight,and especially about 40-60%, is preferred.

The reaction temperature is generally in the range of about 0°-50° C. Itis most often about 0°-40° C and preferably 20°-40° C.

For maximization of the yield and purity of polycyclic oligomers asopposed to high polymer and insoluble and/or intractable by-products, itis preferred to use not more than about 0.7 mole of reagent A(calculated as monomeric material) per liter of organic liquid presentin the reaction system, including any liquid used to dissolve reagent A.Preferably, about 0.003-0.6 mole of reagent A is used when it consistsentirely of reagents A-1 and A-2, and no more than about 0.5 mole isused when it contains reagent A-3. It should be noted that this is not amolar concentration in the organic liquid when reagent A is addedgradually, since said reagent is consumed as it is added to the reactionsystem.

The molar proportions of the reagents constitute another importantfeature for yield and purity maximization. the preferred molar ratoo ofreagent B to reagent A is about 0.1-1.0:1 and most often about0.2-0.6:1. The preferred molar ratio of reagent C to reagent A is about1.5-3:1 and most often about 2-3:1.

Recovery of the poly yclic oligomers normally means merely separatingthe same from diluent (by known methods such as vacuum evaporation) and,optionally, from high polymer and other impurities. When other reagentsare added to reagent C and the preferred conditions and materialproportions are otherwise employed, the polycyclic oligomers (obtainedas a solution in the organic liquid) contain minimal amounts of highpolymer and insoluble material. Depending on the intended use of thepolycyclic oligomer mixture, the separation step may then beunnecessary.

When separation is necessary, the unwanted impurities may be removed inthe necessary amounts by conventional operations such as combining thesolution with a non-solvent for said impurities. Illustrativenon-solvents include ketones such as acetone and methyl isobutyl ketoneand esters such as methyl acetate and ethyl acetate. Acetone is aparticulrrly preferred non-solvent.

The preparation of the polycyclic carbonate oligomers of this inventionsis illustrated by the following examples.

EXAMPLES 2-7

To a solution of 3.53 grams (10 mmol.) of bisphenol A bischloroformatein 10 ml. of methylene chloride was added a solution of 1 mmol. of thedesired tetraphenol in about 0.5 ml. of tetrahydrofuran. The resultingsolution was added over 40 minutes at room temperature, with stirring,to a mixture of 0.25 gram (2.5 mmol.) of triethylamine, 10 ml. of 2.5 Naqueous sodium hydroxide solution (25 mmol.) and 30 ml. of methylenechloride. After the addition was compeete, the organic layer wasseparated, washed twice with 1 N aqueous hydrochloric acid and once withwater and dried. The solvent was removed by vacuum stripping and thepolycyclic oligomers and high polymer were separated by dissolution ofthe polycyclic oligomers in acetone or by precipitation of high polymerfrom methylene chloride by addition of acetone. The results are given inTable I.

                  TABLE I                                                         ______________________________________                                                            Yield, %                                                                            Polycyclic                                                                              High                                      Example                                                                              Tetraphenol        oligomers polymer                                   ______________________________________                                        2      Bis(2,4-dihydroxy-3-                                                                             60        32                                               methylphenyl)methane                                                   3      2,2',4,4'-Tetrahydroxy-                                                                          55        30                                               biphenyl                                                               4      2,2',4,4'-Tetrahydroxybenzo-                                                                     72        26                                               phenone                                                                5      Bis(2,4-dihydroxyphenyl)                                                                         55        33                                               sulfide                                                                6      Bis(2,4-dihydroxyphenyl)                                                                         56        33                                               sulfoxide                                                              7      Bis(2,5-dihydroxyphenyl)                                                                         total 50                                                   sulfone                                                                ______________________________________                                    

EXAMPLES 8-9

To a solution of 17.65 grams (50 mmol.) of bisphenol A bischloroformatein 50 %1. of methylene chloride was added a solution of 5 mmol. of thedeiired tetraphenol in 2 ml. of tetrahydrofuran. The solution was addedover 40 minutes, at room temperature, to a solution of 0.25 gram oftriethylamine in 150 ml. of methylene chloride. There weresimultaneously added 50 ml. of 2.5 N aqueous sodium hydroxide (125mmol.) and an additional 1 gram of triethylamine (total 12.4 mmol.), thelatter being added incrementally. The product was worked upsubstantially as described in Examples 2-7. The results are given inTable II.

                  TABLE II                                                        ______________________________________                                                            Yield, %                                                                            Polycyclic                                                                              High                                      Example                                                                              Tetraphenol        oligomers polymer                                   ______________________________________                                        8      Bis(2,4-dihydroxy-3-                                                                             78        21                                               methylphenyl)methane                                                   9      Bis(2,4-dihydroxyphenyl)sulfide                                                                  75        20                                        ______________________________________                                    

EXAMPLES 10-20

A mixture of 45.6% grams (200 mmol.) of bisphenol A and 200 ml. ofmethylene chloride is stirred as gaseous phosgene is passed in for 50minutes at 0.83 grams per minute (total 420 mmol.). At the same time, 88ml. of 5 M aqueous sodium hydroxide (440 mmol.) is added incrementallyto maintain the pH above 10.0. Stirring is continued for 15 minutes,after which the methylene chloride solution of the crudebischloroformate prodcct is separated and washed with 0.1 M aqueoushydrochloric acid.

The crude bischloroformate product is combined withbis(2,4-dihydroxy-3-methylphenyl)methane and the dihydroxy compounds ordithiols listed in Table III. In each case, the proportions of thetetraphenol and the listed dihydroxy compound or dithiol, based on totalreagent A, are 10 mole percent each. The products are similar to thoseof Examples 2-9.

                  TABLE III                                                       ______________________________________                                        Example   Dihydroxy compound or dithiol                                       ______________________________________                                        10        1,1-Bis(4-hydroxyphenyl)cyclohexane                                 11        1,1-Bis(4-hydroxyphenyl)cyclododecane                               12        2,2-Bis(4-hydroxy-3,5-dimethylphenyl)propane                        13        2,2-Bis(4-hydroxy-3,5-dibromophenyl)propane                         14        Bis(4-hydroxyphenyl) sulfone                                        15        4,4'-Thiodiphenol                                                   16        Bis(4-hydroxy-3,5-dimethylphenyl sulfone                            17        2,2-Bis(4-hydroxyphenyl)-1,1-dichloroethylene                       18        Hydroquinone                                                        19        4,4'-Biphenyldithiol                                                20        1,12-Dodecanedithiol                                                ______________________________________                                    

The polycyclic oligomer mixtures of this invention are useful asintermediates for conversion to crosslinked polycarbonates or theirthiol analogs. Accordingly, the present invention includes a method forthe preparation of a crosslinked resinous composition which comprisescontacting at least one of the previously defined polycyclic oligomermixtures with a polycarbonate formation catalyst at a temperature up toabout 350° C. The oligomer mixtures may frequently be employed in thismethod without separation of high polymer therefrom, but if desired,high polymer may be removed as previously described.

The polycarbonate formation catalysts which can be used in the resinformation method of this invention include various bases and Lewisacids. It is known that basic catalysts may be used to preparepolycarbonates by the interfacial method, as well as bytransesterification and from cyclic oligomers. Reference is made to theaforementioned U.S. Pat. Nos. 3,155,683, 3,274,214, 4,217,438 and4,368,315. Such catalysts may also be used to polymerize the polycyclicoligomer mixtures. Examples thereof are lithium 2,2,2-trifluoroethoxide,n-butyllithium and tetramethylammonium hydroxide. Also useful arevarious weakly basic salts such as sodium benzoate and lithium stearate,as well as tetraarylborates exemplified by the lithium, sodium,tetramethylammonium, tetra-n-butylammonium and tetraphenylphosphoniumtetraphenylborates and similar compounds disclosed in copending,commonly owned application Ser. No. 723,672, filed Apr. 16, 1985, thedisclosure of which is incorporated by reference herein.

Lewis acids useful as polycarbonate formation catalysts includedioctyltin oxide, triethanolaminetitanium isopropoxide,tetra(2-ethylhexyl) titanate and polyvalent metal (especially titaniumand aluminum) chelates such as bisisopropoxytitanium bisacetylacetonate(commercially available under the tradename "Tyzor AA") and thebisisopropoxyaluminum salt of ethyl acetoacetate. Among the preferredcatalysts are lithium stearate and bisisopropoxytitaniumbisacetylacetonate.

The resin formation reaction is typically effected by merely contactingthe polycyclic oligomrs with the catalyst at temperatures up to 350° C,preferably about 200°-b 300° C, until polymerization has proceeded tothe extent desired. Although the use of a solvent is within the scope ofthe invention, it is generally not preferred. In general, the amount ofcatalyst used is about 0.001-1.0 mole percent based on structural unitsin the oligomers.

The preparation of crosslinked resinous compositions according to thisinvention is illustrated by the following examples.

EXAMPLES 21-27

Various polycyclic oligomer compositions of the type described inExample 2-9 were dissolved in methylene chloride; in Examples 22 and 27,high polymer was removed before dissolution. An amount oftetramethylammonium tetraphenylborate to provide 0.1 mole percent basedon stuuctural units in the oligomers was added. The methylene chloridewas removed by vacuum evaporation and the samples were dried at 80° Cfor 2 hours in a vacuum oven. They were then heated under nitrogen at250° C until polymerization was complete. The percentage of crosslinkingwas determined by extracting uncrosslinked material from the sampleswith methylene chloride for 12-16 hours at reflux. The results are givenin Table IV.

                  TABLE IV                                                        ______________________________________                                        Example                                                                              Identity         Mole %   % crosslinked                                ______________________________________                                        21     Bis(2,4-dihydroxy-3-                                                                           5        93                                                  methylphenyl)methane                                                    22*   Bis(2,4-dihydroxy-3-                                                                           5        95                                                  methylphenyl)methane                                                   23     Bis(2,4-dihydroxyphenyl)                                                                       5        70                                                  sulfone                                                                24     2,2',4,4'-tetrahydroxy-                                                                        5        90                                                  biphenyl                                                               25     2,2',4,4'-tetrahydroxy-                                                                        10       89                                                  benzophenone                                                           26     Bis(2,4-dihydroxyphenyl)                                                                       5        90                                                  sulfide                                                                 27*   Bis(2,4-dihydroxyphenyl)                                                                       5        98                                                  sulfide                                                                ______________________________________                                         *High polymer removed.                                                   

The crosslinked resinous compositions of this invention may optionallycontain commonly known and used additives such as, for example,anti-oxidants, mineral fillers, reinforcing agents, impact modifiers,colorants, ultraviolet radiation absorbers such as the benzophenones,benzotriazoles, and cyanoacrylates; color stabilizers such asorganopoosphites; hydrolytic stabilizers such as epoxides; and flameretardants.

Some particularly useful reinforcing agents which may be used separatelyor in combination are carbon, aramid, glass and boron fibers and otherreinforcements which may be chopped, woven, knit, braided, wound orshaped by any conventional method. Some particularly useful flameretardants are the alkali and alkaline earth metal salts of organicsulfonic acids.

What is claimed is:
 1. A composition comprising polycyclic oligomershaving the formula ##STR5## wherein: each R¹ is independently a divalentaliphatic, alicyclic or aromatic radical;each of A¹ and A² is atrivalent aromatic radical; each Y¹ is independently oxygen or sulfur;Y² is a bridging radical in which one or two atoms separate A¹ from A² ;and m and n are integers from 1 to about
 11. 2. A composition accordingto claim 1 wherein each Y¹ is oxygen and each R¹ has the formula

    --A.sup.3 --Y.sup.3 --A.sup.4 --                           (III)

wherein each of A³ and A⁴ is a single-ring divalent aromatic radical andR³ is a bridging radical in which one or two atoms separate A³ from A⁴.3. A composition according to claim 2 wherein each of A¹ and A² is anunsubstituted single-ring aromatic radical and Y² is methylene,carbonyl, thio, sulfoxy or sulfone.
 4. A composition according to claim3 wherein each of A³ and A⁴ is p-phenylene and Y³ is isopropylidene. 5.A composition according to claim 4 wherein a major proportion of theoligomers have degrees of polymerization up to about
 12. 6. Acomposition according to claim 5 which contains about 0.5-10.0 molepercent of units having formula II.